MrBorland, sending you a private message ... Gabby
Sundstrand 15 U type tranny leak...
I bought a non-running John Deere 300 sometime ago and just finished rebuilding the engine. The engine runs fine now, so I hooked up the driveshaft, started it up, and immediately saw tranny fluid is leaking pretty heavily out of the the upper fitting of the suction tube (next to the filter), and I'm looking into why it could be leaking so bad. If anyone's got a guess, please pass it on. FWIW, the check valve adjuster is backed all the way out, but the tractor doesn't move when the lever is moved forward or reverse.
The manual indicates this is a 7/8-14 "O-ring" type of fitting - does this indicate there should be a separate O-ring on the fitting? The fitting's plenty tight, but a missing O-ring could certainly cause a leak.
If I'm reading the circuit diagram right, should be part of the suction flow to the charge pump. If the tractor doesn't move when the shifter is moved, and the suction tube leaks, could the charge pump be creating back pressure?
I haven't yet removed the fender deck to look at the check valves. They were rebuilt, but I suppose the plungers could be stuck in the down position, which would explain why the tractor doesn't move. Would this also explain the leak? Does running the engine/tranny with the check valve plungers depressed create an over-pressure situation which would cause a leak?
If any of you Sundstand experts have any ideas about where to start looking, let me know...
The manual indicates this is a 7/8-14 "O-ring" type of fitting - does this indicate there should be a separate O-ring on the fitting? The fitting's plenty tight, but a missing O-ring could certainly cause a leak.
If I'm reading the circuit diagram right, should be part of the suction flow to the charge pump. If the tractor doesn't move when the shifter is moved, and the suction tube leaks, could the charge pump be creating back pressure?
I haven't yet removed the fender deck to look at the check valves. They were rebuilt, but I suppose the plungers could be stuck in the down position, which would explain why the tractor doesn't move. Would this also explain the leak? Does running the engine/tranny with the check valve plungers depressed create an over-pressure situation which would cause a leak?
If any of you Sundstand experts have any ideas about where to start looking, let me know...
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Key # 13 is a roll pin that needs to be driven out to remove the driveshaft.
I do not know what manual you are reading but my comment is bull. I have remove quite a few driveshafts. The worst I found was on a 314 were that roll pin had sheared but the pieces bound and driveshaft continued to function for quite a while. Broken pin wallowed the bore in the transmission input shaft to the extent I needed to replace the charge pump.
Yes, it can be driven out with the correct size pin punch and a ball peen hammer. I have never needed to soak the roll pin. I am just wondering however if the same thing has happened to you. Pin may have sheared and turned binding the ends of the pin in the ID of of the driveshaft yoke. You may need to slip a pipe or crowbar thru one of the yokes to lock the driveshaft from turning then rock the tractor back and forth to see if the transmission input shaft turns in the yoke.
My 314 gradually lost ground speed was first indication something was wrong. I also have 3ph on the tractor and was losing hydraulic power. Suddenly I lost all ground speed and hydraulic power. The yoke and input shaft were no longer bound but as mentioned serious damage had already occurred. Hopefully you can get the bore in the shaft aligned with the bore in the yoke to drive the pin out.
My 314 gradually lost ground speed was first indication something was wrong. I also have 3ph on the tractor and was losing hydraulic power. Suddenly I lost all ground speed and hydraulic power. The yoke and input shaft were no longer bound but as mentioned serious damage had already occurred. Hopefully you can get the bore in the shaft aligned with the bore in the yoke to drive the pin out.
But before drilling you need to make sure the holes are aligned so you do not damage the input shaft.
There should be a post over on WFM I wrote covering this repair. I thought I might have some photos of this repair but could not find them.
There should be a post over on WFM I wrote covering this repair. I thought I might have some photos of this repair but could not find them.
I am familiar with the pin being longer than the OD of the yoke. Drive in the new pin then push wire thru the pin and wrap the ends with a pair of pliers. Wire is installed to keep the pin from walking out. Set screws would do the same thing but I have never seen this being used. I am going to assume this was a mod during earlier service. Glad to hear you are getting task completed ... Gabby
Further thought. I don't understand how the set screws solve anything. With the set screws why do you need the pin? The pin isn't doing anything but filling a hole drilled in the input shaft. If the pin does protrude into the yoke and the hole diameter in the yoke is larger than the hole in the input shaft the rocking action between the yoke and shaft is only going to shear the pin again. Personally I feel you may need to replace the yoke to get the correct one on the tractor.
Again, good luck with the repair ... Gabby
Again, good luck with the repair ... Gabby
The input shaft to the charge pump is direct drive to the pto output shaft on the top rear of the transmission. If you start the tractor the input and output shaft should both be turning with no activation of the hydrostatic/hydraulic functions. Engage the hydrostats or a hydraulic function. Do both input and out continue to turn? If not you still could have a problem in the input shaft pin.
One other thing to look at. On my 314 after I replaced the charge pump I had similar issue. Nothing worked. A member informed me I installed the pump cover ... key # 8 - https://partscatalog.deere.com/jdrc/sidebyside/equipment/66822/referrer/navigation/pgId/194928 ... upside down. I didn't believe it was possible but after I rotated the cover 180° everything worked fine. Try it ... Gabby
One other thing to look at. On my 314 after I replaced the charge pump I had similar issue. Nothing worked. A member informed me I installed the pump cover ... key # 8 - https://partscatalog.deere.com/jdrc/sidebyside/equipment/66822/referrer/navigation/pgId/194928 ... upside down. I didn't believe it was possible but after I rotated the cover 180° everything worked fine. Try it ... Gabby
Another issue to look at;.does your oil level indicator hose have the breather installed above where you checkt oil level? Breather is between where you check oil level and an adapter back into the transaxle. Without this breather you will not get an accurate oil level in the tube.
Yes there could be a problem with the charge pump but I am checking simple things first. On my 314 I had to swap the pump because the pin between the driveshaft and pump input shaft wallowed out the hole in the input shaft, I was going to replace the shaft but that was a major chore. To replace the shaft required separating the pump from the transaxle. There are some delicate parts in there that need to be handled carefully. I think if these small items do not resolve your issue I would swap the charge pump from your parts tractor. A helper is handy to fit and hold parts being swapped. It's a 4-5 hour job. Replacement pump I used was from a 317. Pumps are universal between closed frame tractors.
Again offering the best with the repairs ... Gabby
Yes there could be a problem with the charge pump but I am checking simple things first. On my 314 I had to swap the pump because the pin between the driveshaft and pump input shaft wallowed out the hole in the input shaft, I was going to replace the shaft but that was a major chore. To replace the shaft required separating the pump from the transaxle. There are some delicate parts in there that need to be handled carefully. I think if these small items do not resolve your issue I would swap the charge pump from your parts tractor. A helper is handy to fit and hold parts being swapped. It's a 4-5 hour job. Replacement pump I used was from a 317. Pumps are universal between closed frame tractors.
Again offering the best with the repairs ... Gabby
It sounds more like electric pto out of adjustment. Nothing to do with hydraulics. Have you done anything with the pto?
Hello @MrBorland
Rear pto on 300 tractor is the transmission tail shaft. You need to remove the fan (key # 2) on the transmission tail shaft ... https://partscatalog.deere.com/jdrc/sidebyside/equipment/66822/referrer/navigation/pgId/178550
Then you add the rear pto shaft kit ... https://partscatalog.deere.com/jdrc/sidebyside/equipment/74757/referrer/navigation/pgId/56162
This pto drive kit is for model 33 tiller. The tail shaft is direct drive. If the engine is running this shaft is spinning. Members use this shaft to power homemade options.
I am not a pro on pto adjustment so I hope other members correct me if I make a mistake. I have had misadjusted front pto drag down the engine. If your pto is not wired I do not think this can happen. Out of curiosity what is the s/n of your tractor? Can you share some overall photos for us to look at to help solve your problem?
Thanks, Gabby
Rear pto on 300 tractor is the transmission tail shaft. You need to remove the fan (key # 2) on the transmission tail shaft ... https://partscatalog.deere.com/jdrc/sidebyside/equipment/66822/referrer/navigation/pgId/178550
Then you add the rear pto shaft kit ... https://partscatalog.deere.com/jdrc/sidebyside/equipment/74757/referrer/navigation/pgId/56162
This pto drive kit is for model 33 tiller. The tail shaft is direct drive. If the engine is running this shaft is spinning. Members use this shaft to power homemade options.
I am not a pro on pto adjustment so I hope other members correct me if I make a mistake. I have had misadjusted front pto drag down the engine. If your pto is not wired I do not think this can happen. Out of curiosity what is the s/n of your tractor? Can you share some overall photos for us to look at to help solve your problem?
Thanks, Gabby
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